Relaxant drugs reduce muscle tone and are used in therapy for the treatment of contractures and muscle spasm. Muscle spasm is one of the main factors responsible for chronic pain; it characterises several pathologies of the locomotor apparatus as well as inflammatory-rheumatic and degenerative orthopaedic pathologies; when it affects articulations, further to pain, it causes rigidity, which reduces joint mobility and flexibility in the affected part. For these reasons, the study of molecules endowed with muscle relaxant and antispasmodic properties still raises remarkable clinical interest.
As it is known, colchicine is a pseudoalcaloid that has been widespreadly used for some time for the treatment of gout. The use of 3-demethyl-thiocolchicine glucoside, thiocolchicoside, is also widespread in therapy for treating contractures and inflammatory conditions that affect the muscular system (Ortopedia e traumatologia Oggi XII, n. 4, 1992). It has been recently shown that the activity of thiocolchicoside is due to its ability to interact with strychnine-sensitive glycine receptors; therefore, compounds having glycine-mimicking activity can be used in the rheumatologic-orthopaedic field, due to their muscle relaxant properties.